NOI = Gross Operating Income – Operating Expenses
Gross Operating Income = Potential Gross Income – Vacancy and Credit Loss
Potential Gross Income = Total possible rental and other income if fully occupied
Operating Expenses = Property-level costs required to run and maintain the property
Exclude mortgage payments from operating expenses
Exclude income taxes from operating expenses
Exclude depreciation from operating expenses
Exclude capital expenditures from operating expenses
Exclude tenant improvements from operating expenses
Exclude leasing commissions from operating expenses
Add other property income to rental income before subtracting expenses
Use the same time period for all income and expense figures
Verify all recurring income and recurring operating costs are included
Subtract total operating expenses from total gross operating income to get NOI